Automatic series cut-out



June 14, 1932. R ROWE AUTOMATIC SERIES CUT-OUT Filed De c. 26. 1950 2 Sheets-Sheet l June 14, 1932. R ROWE 1,862,830

AUTOMATIC SERIES CUT-OUT Filed Dec. 26. 1950 2 Sheets-Sheet 2 Patented June 14, 1932 UNITED STATES PATENT OFFICE RAYMOND ROWE, OF PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE STATES COM- PANY, OF HARTFORD, CONNECTICUT,- A CORPORATION OF CONNECTICUT AUTOMATIC SERIES CUT-OUT Application filed December 26, 1930.

This invention relates to those devices which are provided for automatically disconnecting a defective portion of a series circuit and still keep the remainder of the circuit in operation, and more particularly to breaks, of the type in which there is a spark gap so located that when a break occurs the potential difference of the line across the gap will be sufficient to break down the gap and close a circuit through a'solenoid that will cause a switch to disconnect the section of the circuit containing the defect and by-pass the spark gap.

The object of this invention is to so construct a device of this character that it will not operate to disconnect a section of the line protected by the deviceunder the effect of abnormal voltage conditions, such as induced voltages due to lightning discharges.

In the embodiment of the invention illustrated this object is attained by providing an automatically adjustable spark gap which when conditions are normal is so wide that current of abnormal voltage will not jump the gap, but when a break occurs in the section of the line protected by the device, the width of the gap is so reduced that the potential difference of the line will be sufficient to cause the current to jump the gap and operate a switch to cut out the opened section of the line and close the remainder of the line.

Fig. 1 of the accompanying drawings shows a side elevation of the device with a portion of the insulating body broken away. Fig. 2 shows a front elevation with the means for automatically adjusting the air gap in section. Fig. 3 is a diagram illustrating the wiring connections of the device.

The main body 1 of the device illustrated is formed of a single piece of insulation, desirably bakelite. Located in an opening in the body is a lifting solenoid which is preferably composed of fixed series connected, fine wire coil 2 of many turns, and coarse wire coil 3 of few turns, and a vertically' movable core 4. This core is connected by strip 5 Serial No. 504,821.

with a bar 6 of insulating material that extends horizontally across the top of the body and at one end has a conducting blade 7 and at'the other end a conducting blade 8.

In normal operation the bar is in its lower position with the blade 7 in engagement with a conducting brush 9 and the blade 8 in engagement with the conducting brush 10. Thebrush 9 is connected by a conductor 11 with one side of the loop 12 which is to be protected by the device, and the brush 10 is connected by a conductor 13 with the other side of the protected loop. The blade 8 is connected by a conductor 14 with one side of the main loop 15, and the blade 7 is connected by a conductor 16 with one end of a coil 17, the other end of which coil is connected by conductor 18 with the other side of the main loop 15. The terminals of this main loop 15 are connected with the source of current, which may be the secondary of a transformer 19.

In the coil 17 is a core 20 with a plate 21 that forms one electrode of the spark gap 22. The core 20 is connected by a flexible conductor 23 with the conductor 18. The lower end of the coil 2 is connected byconductor 24 with a conducting plate 25 which is fixed to the top of the body and forms the other electrode of the spark gap. The upper end of the coil 3 is connected by conductor 26 with the conductor 14. A high resistance 27 may be connected between the line 14 and the lower end of the coil- 2. I When the bar 6 is lifted the blade 8 is disengaged from the brush 10, and the blade 7 is disengaged from the brush 9 and engaged with a brush 28 which is connected by a conductor 29 with the solenoid coils 2 and 3, preferably at their junction.

The coil 17 is held between plates 30 that are spaced apart by posts 31, the lower of which plates is fastened on the hub 32 of the insulating body of the device. Threaded through the upper plate is a sleeve 33 that is adjustable up and down, and threaded on the sleeve is a nut 34. The stem 35 of the core 20 extends loosely through the sleeve 33 and at its upper end is provided with a stop nut 36 and lock nut 37. By adjusting the sleeve 33 the upper limitof movement of the core 20 may be determined, and by adjusting the nuts 34, 36 and 37 the lower limit of movement of the core 20 may be determined. The nut 34 is preferably hexagonal and after it has been adjusted to the desired position it is retained against movement by a spring 38. By this means the maximum and minimum distances apart of the movable spark electrode 21 and the fixed spark electrode 25 may be accurately regulated.

In operation under normal conditions current to the loop 12 protected by this device, passes from an end of the loop 15 through conductor 18, the solenoid coil 17 and conductor 16 to the movable blade 7 that at this time "is engaged with the lower fixed brush 9. From this brush current flows through the c0nductor 11 to a terminal of the protected loop 12. From the other end of the loop 12 current passes through conductor 13 to the lower fixed brush 10 which is engaged by a movable blade 8. From this blade current passesthrough the conductor 14 to a terminal of the loop 15, the ends of which are connected with the source of energy 19. Under normal conditions current flowing through the solenoid coil 17 lifts the movable solenoid core 20 and the spark electrode 21. and opens the spark gap 22 to its widest extent, that is, to an extent which is sufiicient to prevent the gap from being broken down by the line potential or by abnormal potential, such as would exist from induced voltage due to lightning discharge. lVith these connections no current passes through the solenoid coils 2 and 3 owing to the resis ance oifered by the gap.

Should a break occur in the loop 12 protected by this device, for an instant no current would flow through the solenoid coil 17 which becoming de-energized would allow' the core 20 and electrode 21 to drop and reduce the width of the spark gap, as indicated in dotted outline in Fig. 3. The full potential difi'erence of the line would then exist across the reduced gap, and this would break down the gap and close the circuit across the gap from one side of the loop 15 through conductor 18, conductor 23. core and electrode 21, to the electrode 25 which is connected with the solenoids 2 and 3 that are in series and are connected by conductor 26 with the other side of the loop 15. The energized coils 2 and 3 then cause its core to lift the bar 6 and disengage the movable blade 8 from the fixed brush 10 and disengage the movable blade 7 from the fixed brush 9 and engage the blade 7 with the fixed brush 28. Both sides of the loop 12 are thus disconnected. Current will now pass from blade 7 through brush 28 and conduct-or 29 to solenoid coil 3 and then through conductors 26 to a terminal of the loop 15. The solenoid coil 2- is wound so as to lift the core quickly, and the solenoid coil 3 is wound to hold the core up with the movable blade 7 held firmly in engagement with the upper fixed brush 28. Current restored through these connections passes through and energizes the solenoid coil 17, so its core 20 lifts the electrode 21 to its upper position, and the arc discontinues as the current is shunted around the gap. In practice these actions occur almost instantly and result in cutting out the disrupted loop and restoring the circuit through the remainder of the line.

The invention claimed is:

1. A cut-out comprising fixed contacts designed to be connected with a loop to be protected, movable contacts normally engaged with said fixed contacts, one movable contact being connected with one side of the current source and the other movable contact being connected with a solenoid coil that is connected with the other side of the current source, said coil having a movable core with a gap electrode that is connected with the current source on the same side as the coil, a solenoid coil with a. core connected to lift said movable contacts from the fixed contacts when said coil is energized, said latter coil having one terminal connected with the current source and its other terminal connected with a fixed gap electrode, and a fixed contactconnected with said latter coil and adapted to be engaged by one of said movable contacts when said coil is energized, whereby under normal operation the current causes a wide gap to exist between said electrodes and interruption of the current causes a reduction in the gap.

2. A cut-out comprising fixed contacts designed to be connected with a loop to be protected, movable contacts normally engaged with said fixed contacts, one movable contact being connected with one side of the current source and the other movable contact being connected with a solenoid coil that is connected with the other side of the current source, said coil having a movable core carrying a gap electrode which electrode is connected with the current source on the same side as the coil, a lifting solenoid having a fine wire coil and a coarse wire coil connected in series, and a movable core adapted to lift said movable contacts from the fixed contacts when said coils are energized, said coarse coil being connected with one side of the current source and said fine coil being connected with a fixed gap electrode that is complementary to the electrode carried by the movable core of the first mentioned coil, and a fixed contact connected at the junction of said coils and adapted to be engaged by one of said movable contacts when said lifting solenoid is energized.

3. A cut-out comprising fixed contacts designed to be connected with a loop to be protected, movable contacts normally engaged with said fixed contacts, one movable contact being connected with one side of the current source and the other movable contact being connected with a solenoid coil that is connected with the other side of the current source, said coil having a movable core carrying a gap electrode which electrode is connected with the current source on the same side as the coil, a lifting solenoid having a fine wire coil and a coarse wire coil connected in series, and a movable core adapted to lift said movable contacts from the fixed contacts when said coils are energized, said coarse coil being connected with one side of the current source and said fine coil being connected with a fixed gap electrode that is complementary to the electrode carried by the movable core of the first mentioned coil, a resistance coil between said fine wire coil and the current source, and a fixed contact connected at the junction of said coils and adapted to be engaged by one of said movable contacts when said lifting solenoid is energized.

4. An automatic series cut-out comprising movable conductors normally closing a circuit through a loop to be protected, a normally lIIELCtiXe solenoid energized on the disruption of the loop circuit and disconnecting said conductors from the loop circuit and closing a circuit across the loop, said solenoid being connected between a fixed spark gap electrode and the current source and also connected with one of said movable conductors, and a normally energized solenoid connected between. the current source and the other movable conductor, said solenoid controlling a movable spark gap electrode that is connectedwith the current source, said movable electrode being normally retained at a distance from said fixed electrode but allowed to approach the fixed electrode when the last mentioned solenoid is de-energized.

5. An automatic series cut-out comprising movable conductors normally closing a circuit through a loop to be protected, normally inactive means energized on the disruption of the loop circuit and disconnecting said conductors from the loop circuit and closing a circuit across the loop, said means being connected between a fixed spark gap electrode and the current source and also connected with one of said movable conductors, and

loop circuit and closing a circuit connected with the source of current, and electro-magnetic means normally energized and controlling a spark gap which has an electrode connected with the current source and an electrode connected with the first mentioned means, which second mentioned means is deenergized when the loop circuit is disrupted and causes the spark gap to be reduced.

7. The combination in an automatic series cut-out having means normally closing a circuit through a loop to be protected and disconnecting said loop and closing a circuit connected with the source of current on the disruption of the loop circuit, of spark gap electrodes one of which is connected with said first mentioned means and the other with the current source, and means normally retaining said electrodes with a wide air gap, but reducing the distance between them upon the disruption of the loop circuit to such an extent that current from the source will cause the first mentioned means to disconnect the current source from the disrupted loop.

RAYMOND N. ROWE. 

